Add system-info macOS user agent

The `system-info` directory contains scripts and configuration files to
install and remove a `launchd` user agent on macOS which collects
information about the system and outputs it to the file
`~/.cache/tmux/system-info`. This file is then read periodically by
`tmux` and the contents displayed in the status line.

.conduit.yaml

@@ -27,3 +27,6 @@
       dst: ~/.local/share/tmux/layouts/window-wide-left
     - src: layouts/window-wide-right
       dst: ~/.local/share/tmux/layouts/window-wide-right
+- command:
+    - install: system-info/install.sh
+    - remove: system-info/remove.sh

system-info/install.sh

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+script_dir=`dirname $0`
+
+if [ `uname` = Darwin ]; then
+  cp $script_dir/system-info.plist ~/Library/LaunchAgents/system-info.plist
+  launchctl load -w ~/Library/LaunchAgents/system-info.plist
+fi

system-info/remove.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+
+if [ `uname` = Darwin ]; then
+  launchctl unload ~/Library/LaunchAgents/system-info.plist
+  rm ~/Library/LaunchAgents/system-info.plist
+fi

system-info/system-info-macOS.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+cache_dir=~/.cache/tmux
+cache_file=$cache_dir/system-info
+
+# Make sure the output directory exists.
+if [ ! -d $cache_dir ]; then
+  mkdir -p $cache_dir
+fi
+
+# Cleanup cache file when interrupted.
+trap '[ -f $cache_file ] && rm $cache_file; exit' INT
+trap '[ -f $cache_file ] && rm $cache_file; exit' TERM
+
+while true; do
+  battery="`pmset -g batt | grep --color=never -Eo '\d+%'` ↯"
+  echo "$battery" > $cache_file
+  sleep 2
+done

system-info/system-info.plist

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+  <dict>
+    <key>Label</key>
+    <string>system-info</string>
+    <key>ProgramArguments</key>
+    <array>
+      <string>/Users/benie/.config/tmux/system-info/system-info-macOS.sh</string>
+    </array>
+    <key>KeepAlive</key>
+    <true/>
+  </dict>
+</plist>

tmux.conf

@@ -124,11 +124,8 @@ setw -g status-left-style fg=colour240,bg=colour233
 # Centre status style
 setw -g status-style fg=colour240,bg=colour233
 
-# Right status style, show data and time (and battery percentage on macOS).
+# Right status style shows system info, date, and time.
-if '[ "`uname`" = "Darwin" ]' \
+setw -g status-right "#(cat ~/.cache/tmux/system-info) %a %d-%m-%y %H:%M "
-  'setw -g status-right "#(pmset -g batt | grep --color=never -Eo \"\\d+%%\")\
- ↯ %a %d-%m-%y %H:%M "' \
-  'setw -g status-right "%a %d-%m-%y %H:%M "'
 setw -g status-right-style fg=white,bg=colour233
 
 # Active window status style